<!DOCTYPE html>
<link rel="help" href="https://www.w3.org/TR/1999/REC-xpath-19991116/#function-id">
<body>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>
<script>
// Test the id() function with various scenarios
function testIdFunction(expression, xmlString, expectedIds) {
  let doc = (new DOMParser()).parseFromString(xmlString, 'text/xml');
  test(() => {
    let result = doc.evaluate(expression, doc.documentElement, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
    assert_equals(result.resultType, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE);
    let actualIds = [];
    for (let i = 0; i < result.snapshotLength; i++) {
      actualIds.push(result.snapshotItem(i).getAttribute('id'));
    }
    actualIds.sort();
    expectedIds.sort();
    assert_array_equals(actualIds, expectedIds, `Expected IDs ${expectedIds}, got ${actualIds}`);
  }, `${expression}: ${doc.documentElement.outerHTML}`);
}

// Test single ID
testIdFunction('id("test1")', '<root><div id="test1">Match</div></root>', ['test1']);

// Test multiple IDs in space-separated string
testIdFunction('id("test1 test2")', '<root><div id="test1">First</div><div id="test2">Second</div></root>', ['test1', 'test2']);

// Test non-existent ID
testIdFunction('id("nonexistent")', '<root><div id="test1">No match</div></root>', []);

// Test mixed case IDs (should be case-sensitive)
testIdFunction('id("Test1")', '<root><div id="test1">No match</div></root>', []);

// Test multiple elements with same ID (should return all)
testIdFunction('id("duplicate")', '<root><div id="duplicate">First</div><div id="duplicate">Second</div></root>', ['duplicate', 'duplicate']);

// Test IDs with special characters
testIdFunction('id("test-1")', '<root><div id="test-1">Match</div></root>', ['test-1']);

// Test empty ID string
testIdFunction('id("")', '<root><div id="">Empty ID</div></root>', []);

// Test whitespace in ID string
testIdFunction('id(" test1 ")', '<root><div id="test1">Match</div></root>', ['test1']);
</script>
</body>
